Photocatalytic degradation of ciprofloxacin by Gd-Co/g-C3N4 under low-power light source: Degradation pathways and mechanistic insights
Yalin Zeng, Lieshan Wu, Jingjing Luo, Xiaowei Lu, Bing Jia, Liuling Liang, Jing Zhang
Abstract
Ciprofloxacin hydrochloride (CIP) is remained in the natural environment. Photocatalysis is a promising technology for removing hard-to-degrade pollutants from water. For this purpose, we constructed a three-dimensional porous structure of graphitic-phase carbon nitride (3D g-C 3 N 4 ) and doped rare earth element Gd and metal Co into 3D g-C 3 N 4 to form a photocatalyst (Gd-Co/CN). We conducted photocatalytic experiments to evaluate its photocatalytic activity with CIP as the target pollutant. Experimental results showed that Gd-Co/CN had the best photocatalytic degradation of CIP under a 30 W LED lamp . The increase in photocatalytic activity is mainly attributed to the doping of Gd and Co expanding the specific surface area of 3D g-C 3 N 4 , and providing more reaction sites for photocatalytic reactions. Gd-Co/CN enhances O 2 adsorption and activation and generates radicals ( O 2 − and h + ), allowing efficient degradation of CIP under low-power light sources . Furthermore, Gd-Co/CN also showed excellent stability and reusability in cycling experiments. This study explored the degradation pathways and mechanisms of CIP by using ultra-high-performance liquid chromatography and mass spectrometry (HPLC-MS) and density functional theory (DFT). It provides a more energy-efficient and environmentally friendly method for the treatment of antibiotic wastewater.